I just bought a new case of wolf 7.62x39 fmj's, prior to this I have used wolf, herters, barnaul and tulammo with no malfunctions. Now i'm getting pretty frequent fte's where the casing is extracted but not kicked out causing a jam. I did take the bolt apart and noticed that it doesnt have the rubber nub in the extractor spring so I'm going to add one to add extractor strength, other than this what should I do next? I'm thinking my next step will be an adjustable gas block as the primers are much more flattened than all previous ammo used, so I suspect this ammo is over gassing it. This will also help me sort out the sharp recoil rather than buying a heavy buffer and heavy spring, so it is the next progressively cheaper step if that makes any sense.

Make sure the ejector is not stuck and is moving freely. The little hole on the side of the bolt is to oil the ejector.

Seems if your setup is overgassed you'd have experienced these issues from day 1. I'd clear any issues with the extractor first and scrub the chamber if there's any carbon build up in there. Otis makes a nice 7.62 AR chamber brush.

I think this batch of wolf is higher pressure as the prior stuff showed normal primer pressure but this stuff shows very flattened primers. It had pretty sharp recoil and the buffer is getting beat up to boot but had been totally reliable.

I will double check that, I broke my ankle while instructing use of force scenarios and will be off work for 30 days now. At least I didn't damage my m-16 sim gun when I went down,lol, my ankle will heal but a properly functioning m-16 sim gun is about impossible to replace. Sort of stuck in the house for now, hope my bank account can handle it, I've already bought a new Mega lower out of boredom. DAMN internet shopping!

The rubber nub (extractor upgrade) seems to have worked! I'm still going to either get an adjustable GB or heavier springs and buffer  to slow things down.

Update.....

Though the FTE problem seemed to be cured by the extra rubber nub I felt that the system was out of whack in 2 ways leading to this malfunction with wolf. 1st the ejector was overpowering the extractor, there needs to be the proper balance between the ejector and extractor. If the ejector is over powering the extractor then it will release the case prematurely, leaving it in the action jamming the next round coming up from the mag.  second I think the bolt was disengaging too fast, causing a harsh rapping that you could feel in your cheek, it was uncomfortable and not good for the system, so it needed to be slowed down.

Adjustments......

To tune the ejection/extraction,  I bought a sprinco xp 5 coil extractor spring, I also had an o-ring and a rubber insert. I add them all on until the extractor was overpowering the ejector (the cartridge wouldn't get spit out reliably). At this point I removed the o-ring and checked for proper function (you should be able to pull the bolt back and the ejector should spit it out on to the floor even when manipulating the bolt rather slowly). Perfect!

Slowing the bolt.....

I bought a red sprinco buffer spring and replaced the stock one. The difference was pretty noticeable, the harsh rapping was gone , I will probably still add a H2 buffer since I worry that the bolt will be travelling forward too fastnot giving some crappier magazines time to feed the next round ect.... but honestly I haven't had any malfunctions since I did all this and my round count is up to 500.

This is making me feel better about my parts choices for my built
Sprinco Red and extractor spring upgrade
H2
Adjustable gas block
Maxim bolt

A heavy Sprinco buffer spring seemed to really improve the operation of my Colt 14.5" upper.  I get 3 o'clock ejection with a can, 6 o'clock without.  Wolf poly ammo.

I never did get my DPMS running as reliably.  My malfunctions were always nosedives in the magazine, but the Colt runs fine with the same mags.  I tried the Sprinco springs in it too.  I also changed all mag springs to heavy AK47 springs.  

I run CP mags that were the last ones before they sold out or whatever happened.  I have two DPMS frankenmags that run great too.

The spring is cheap.  Get a few and try them in some of your .223 rifles too.  I have one in my 9mm.

The new c products have a new follower that might have prevented the nose diving. I really like them though like a lot of other things, they seem to work smoother with a little use.

OP, can you measure your rifling grooves and tell us if they are .311" or .308"?

I'll have to see if I can find my caliphers. Judging by recovered bullets Ide have to say it is around .311, I do have a .308 barrel on another rifle that will wipe most of the copper wash off the bullet, other than that it shoots really well. I've shot 7.62x54 rifles with .308 barrels with steel cored surplus with no I'll affects so, I'm not too worried about pressure. The Fin's purposely retrofitted .308 barrels on there various models of mosins knowing they would be shooting captured Russian ammo that often measured .312. I do think a .308 barrel will wear much faster though.

Pressure will increase significantly with a .308 pipe shooting .311" pills, enough to push well outside of the intended chamber pressure of 7.62x39, increase bolt thrust, and also drive the gas system much harder.

The Finns (that's my people now we're talking about now) used both barrel diameters in the 1920's and 1930's.

The Mosin-Nagants they inherited from the Czarist times were .311".  In the 1920's, shortly after Finnish independence and the Finnish Civil War, the White Guard Nationalists prevailed, and launched an active reserve training program to maintain a vigilant defense posture.  There was a program instituted to rebuild the Mosin's into more accurate, Finnish specific configurations that would step away from the crude Slav condition of the rifles.

Part of that program was to re-barrel the rifles with highly accurate pipes. There was a period where they did use .308", but they went back to .311".  I have an LS26 LMG barrel from that era, and it has the tighter bore.

A lot of the real late m39's they used in their marksmen's program had them too, I sure love those crafty finns, they made and make a mean rifle and then of course gave the soviet army a big black eye.  I agree it raises pressures some but I don't think it as much as people think.

Go to the 6mmAR website and perform the ejector modification they suggest on your rifle. It can be done two different ways, I suggest removing it and chucking it in a drill. The rounded ejector is similar to the Dutch modification of AR10 ejectors and help improve reliability. Larger diameter cartridges in AR15 uppers really need this done.

EDITED TO ADD: Robert Whitely, owner of the 6mmAR website posted his ejector modifications in articles run on www.accurateshooter.com, not on his 6mmAR site.  He is the best source I know of for wildcat AR's.

Dutch Armalite AR10 radiused ejector on production guns:

You know the old yhm 7.62x39 ejectors are rounded just like that, very interesting.

Very nice.  Can you please link the article that discusses the ejector modification?

I have been searching his site without any luck.  I don't doubt its right under my face.

Bump to see if someone can link the article.  

Get the Brownell's bolt disassembly tool.

Follow instructions for removal of your ejector (you shouldn't need instructions at this point).

I like to spin the ejector in a drill so I can put the radius on it, but you don't need a full radius either.  There is only one side of it that can arrest the alignment of the case, so that is all that needs the edge take off.

If you do it too deeply or aggressively, you will cause more brass shear into the ejector channel, clogging the ejector with shavings.

Will do.  I have a bolt disassembly tool.  You think I have to register there to read that article?   I'm sure if they have that article, there maybe more article worthwhile.